Diagnostic Value Of ANI And Combined With Gamma-glutamyl Transferase In Differentiating ALD And NAFLD

Object: This study aimed to verify the reliability of the ALD/NAFLD index(ANI) for distinguishing alcoholic liver disease(ALD) in patients with hepatic steatosis from nonalcoholic fatty liver disease(NAFLD), and to investigate whether ANI combined with gamma-glutamyl transferase(GGT) would enhance the accuracy of diagnosis in China.Methods: 139 cases of fatty liver disease(FLD), according to liver histopathologic examination and the diagnostic criteria of The Chinese National Workshop on Fatty Liver and Alcohol Liver Disease for the Chinese Liver Disease Association, were divided into two groups of ALD and NAFLD. Parameters for ANI are aspartate aminotransferase(AST), alanine aminotransferase(ALT), mean corpuscular volume(MCV), body mass index(BMI), and sex. ANI was calculated using an online calculator. The biochemical indicators and ANI value were analyzed using statistical methods.Results: 1. ANI was significantly higher in patients with ALD than in those with NAFLD(7.11 ± 5.77 vs.-3.09±3.89, P <0.001). With a cut-off value of-0.22, the sensitivity, specificity, and area under the receiver-operating characteristic curve(AUROC) of diagnosed ALD cases was 87.1%, 92.5%, and 0.934(95% CI: 0.879-0.969), respectively. The corresponding values for AST/ALT, MCV, and GGT were 75.29%, 72.94%, and 0.826(95% CI: 0.752-0.885); 94.34%, 83.02%, and 0.814(95% CI: 0.739-0.875) and 80.23%, 79.25%, and 0.815(95% CI: 0.740-0.876), respectively. ANI AUROC was significantly higher than the AST/ALT, MCV or GGT AUROCs(all P<0.001), moreover, ANI showed better diagnostic performance. The difference in AUROCs between AST/ALT, MCV, and GGT was not statistically significant(all P>0.05).2. When combined with ANI and MCV or AST/ALT, its AUROC of differentiating diagnosis was 0.904(95%CI:0.895-0.973)、0.936(95%CI:0.899-0.975) respectively, the difference in AUROCs with ANI was not statistically significant(P>0.05). However, the combination of ANI and GGT showed a better AUROC than ANI alone(0.976 vs. 0.934, P=0.016).3. When ANI joint GGT for diagnosis of ALD patients with different ages showed that the diagnosis of ALD patients with 13 to 29 years,the sensitivity and specificity were 100% and AUC(95% CI) was 1.000(0.794-1.000). At the same time, the corresponding 30 to 49 years, 50 to 69 years ALD patients, the diagnostic sensitivity, specificity and AUC were 82.05%, 95.45%, 0.917(0.818-0.972) and 97.62%, 93.75%, 0.988(0.917-1.000) respectively. In ≥70 years, sensitivity, specificity and AUC was 50%, 100%, 0.500(0.07-0.932) respectively. The difference of AUC in 13 to 29 years and 50 to 69 years was not statistically significant(P> 0.05), while the difference between 30 to 49 years and 50 to 69 years AUC presence of statistically significant difference(P <0.05). Moreover, the AUC in the 30 to 49 years and ≥70 age group also exist significant differences(P <0.05).Conclusions: Our study validated ANI scoring system to identify ALD and NAFLD with high accuracy in Chinese population. When ANI >-0.22, support the diagnosis of ALD, while ANI >-0.22, was more likely to be NAFLD. Meanwhile, when combined with ANI and GGT, its accuracy of differentiating diagnosis had been further improved. And when combined with ANI and GGT showed the highest diagnostic accuracy in ALD patients with 13 to 29 years and 50 to 69 years, which in the 13 to 29 age group was 100% accurate. Followed by the 30 to 49 age group. Diagnostic accuracy was minimum in ≥70 age group, only 50%. Although ANI scoring system itself has certain limitations, and still cannot replace histopathologic examination for diagnosis of ALD and NAFLD, it may assist in distributing triaging patients for liver biopsy.